site banner
PaperclipPerfector  2d ago (text post)   1860 thread views

Small-Scale Question Sunday for July 26, 2026

Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?

This is your opportunity to ask questions. No question too simple or too silly.

Culture war topics are accepted, and proposals for a better intro post are appreciated.

1
Top Bottom Old Controversial Comments
Jump in the discussion.

No email address required.

Can anyone comment on the dangers of drinking low total dissolved solids (TDS) reverse osmosis water on general health, especially with a baby in the home? I recently installed a reverse osmosis filter and then discovered that low TDS water can potentially be dangerous because of a lack of minerals like calcium, magnesium, and phosphate. My RO filter doesn't have a remineralization add-on.

One reverse osmosis study from India

Assume that me and my baby otherwise have the very best foods and baby formula available. Some random reddit comments indicate that eating a high quality diet filled with meats, fish, and vegetables accounts for 97% of mineral intake, so there's no need to worry. Or is there? Is reverse osmosis water unusually leeching of minerals in some way?

I'm not that worried for myself because I add in keto salts for my water while fasting, so my water is already remineralized. But is it bad for a growing child? I'm not feeding my family the typical SAD diet, they get the best home cooked meals made with fresh groceries that we can afford.

Absolute nonsense. The amount of minerals in water is very minimal, and most of what is there is sodium, which people generally have too much of.

Calcium and Magnesium are the two you might miss, and see below for how jack shit nothing it'd take to replace that with food. The health crazies conflate that pure water leaches minerals out of things (true) with the amount being relevant (false). You have plenty of minerals to spare in your body.

Below stats are for typical tap water. Double them if you have hard water.

The target is just two numbers: 120 mg calcium and 47 mg magnesium. Everything else the water gives you is nutritionally negligible, so ignore it.

Best single food: chia seeds, 19 g (90 kcal) — 120 mg calcium, 64 mg magnesium. Overshoots magnesium slightly, hits calcium exactly. Sesame seeds do it in even less mass (12 g, 70 kcal) but come with a bioavailability problem, below.

Best two-food pairing: 10 g parmesan + 9 g pumpkin seeds (90 kcal, 19 g total). Splits the job cleanly — the cheese covers calcium at 118 mg, the seeds cover magnesium at ~47 mg.

Calorie-minimal: 100 g skim milk + 6 g wheat bran (46 kcal). Milk delivers the 120 mg calcium in 34 kcal with dairy-grade absorption; bran is the densest magnesium source that exists at 610 mg/100 g, so 6 g covers 37 mg and the milk supplies the remaining 11 mg.

So: roughly a tablespoon of seeds, or a splash of milk and a spoonful of bran. Under 100 kcal any way you slice it, often under 50.

Why are you doing reverse osmosis on your water? It sounds like an expensive way to treat it with no obvious benefit.

The intuition for why distilled water is bad, is that it will leech out minerals from your cells through osmosis. Obviously, there are no human trials to prove this, as is pointed out below (do note that the paper cited in that comment is not peer reviewed, and only "published " on researchgate, so take it with a grain of salt). It is entirely possible that this is a story made up by chemistry teachers to keep students from drinking it. This has historically not been studied, as distilled water is expensive and there is no obvious reason for drinking it instead of tap/bottled water.

I would say "ask your doctor", but frankly your dietary choices seem speculative enough that there won't be significant amount of research done on them, and so no real authoritative evidence in any direction.

I think you need to face that you are running a dietary experiment here. You are going to have to be the expert.

I've at least heard this claim uncited before. Isn't reverse osmosis filtering pretty ubiquitous on ships these days? I'm not aware of any literature suggesting major health impacts from this to sailors or long-term cruise passengers, for example. But maybe tossing in a multivitamin wouldn't be terrible.

ETA: I assume desalination plants like those in the news in the Middle East also use RO.

I got it from chemistry teachers and people working in labs. It might just be something they say to keep people from drinking it. Just like the story that the lab ethanol is treated with something that makes you puke, so that students won't steal it for their parties.

Just like the story that the lab ethanol is treated with something that makes you puke

But that's real. They add bitterants and sometimes toxic chemicals to lab ethanol. They purposefully contaminate it.

That seems counterproductive to doing experiments. You would want your solvents to be as uniform as possible, to ensure that your study conditions can be replicated and verified by others.

To be fair, lab ethanol probably will make you puke (eventually).

According to the research I remember it's more like "don't drink distilled water regularly" than "one glass and you suffer", and only the latter story would make sense as being made up so students don't drink lab-quantities of it.

As for technical ethanol, pretty sure they do treat it to taste foul at least.

"Ethanol" in a school chemistry lab is probably meths - the duty on drinkable pure alcohol is pretty high, even if not marketed for drinking. Adding 5-10% methanol makes the alcohol too toxic to drink and therefore unattractive to drinkers. We were all warned about this in no uncertain terms before doing an experiment with the stuff.

In the UK, they don't add anything additional to meths to make it unpalatable, so ocasionally tramps and suchlike posion themselves by drinking it. Meths sold to the general public as a fuel/cleaning product is died purple to discourage accidental drinking. But a school science lab is going to be using "industrial methylated spirits" - i.e. an ethanol/methanol mix with nothing else added to it that could affect the chemistry. (Of all the chemicals in my school lab, this was oddly the only one they needed a licence to buy).

I'm not sure about the situation in the US.

Most alcohol poisoning in the US is using homebrew that was messed up somehow. Sometimes this is a fungal contamination and sometimes it's making methanol instead of ethanol. Industrial alcohol contains something to render it undrinkable, but this is normally gasoline rather than methanol.

Wouldn't that cause a problem in the lab by making the "alcohol" immiscible with water?

For industrial uses? I’m not sure what they do in chemistry labs.

We are talking about replacing your daily water intake entirely. I agree that the claim seems unlikely when you consider it seriously though. The more relevant question is why would you want to distill your drinking water in the first place?

My local groundwater was contaminated and has been the focus of a regional cleanup effort over decades, with the cleanup pumps are still actively filtering the water. About half of my neighbors have both water softening and a undersink RO system for their families. It wasn't that expensive compared to buying bottled or delivered water either, about $300 for the RO system and ~$150 in yearly replacement filters.

At least some people are using distillation or reverse osmosis for desalination. I'd do that too if my only water supply was the ocean.

Im not a doctor and you are probably better off asking an AI. But I do know that the problem with distilled water is the leeching of minerals. It's not that water is supposed to provide a bunch of minerals, it doesn't.

The water that goes into you will balance with the water in your system. Which is why drinking salt water can dehydrate you. Or why Gatorade was designed to be an effective sports drink, it's supposed to mimic the balance of water in your body, to prevent the leeching of minerals or water to balance out what is being added.

If you are in the US tap water is safe and fine.

But I do know that the problem with distilled water is the leeching of minerals.

Which doesn't even happen in the first place.

What is this place?

This website is a place for people who want to move past shady thinking and test their ideas in a court of people who don't all share the same biases. Our goal is to optimize for light, not heat; this is a group effort, and all commentators are asked to do their part.

The weekly Culture War threads host the most controversial topics and are the most visible aspect of The Motte. However, many other topics are appropriate here. We encourage people to post anything related to science, politics, or philosophy; if in doubt, post!

Check out The Vault for an archive of old quality posts. You are encouraged to crosspost these elsewhere.


Why are you called The Motte?

A motte is a stone keep on a raised earthwork common in early medieval fortifications. More pertinently, it's an element in a rhetorical move called a "Motte-and-Bailey", originally identified by philosopher Nicholas Shackel. It describes the tendency in discourse for people to move from a controversial but high value claim to a defensible but less exciting one upon any resistance to the former. He likens this to the medieval fortification, where a desirable land (the bailey) is abandoned when in danger for the more easily defended motte. In Shackel's words, "The Motte represents the defensible but undesired propositions to which one retreats when hard pressed."

On The Motte, always attempt to remain inside your defensible territory, even if you are not being pressed.


New post guidelines

If you're posting something that isn't related to the culture war, we encourage you to post a thread for it. A submission statement is highly appreciated, but isn't necessary for text posts or links to largely-text posts such as blogs or news articles; if we're unsure of the value of your post, we might remove it until you add a submission statement. A submission statement is required for non-text sources (videos, podcasts, images).

Culture war posts go in the culture war thread; all links must either include a submission statement or significant commentary. Bare links without those will be removed.

If in doubt, please post it!


Rules


Recommended Posts And Communities

Recommended Realtime Chats